Organic light emitting display apparatus and method of manufacturing the same

ABSTRACT

Provided are an organic light-emitting display apparatus and a method of manufacturing the same. An organic light-emitting display apparatus includes: a substrate including an active area and a pad area, an anode electrode in the active area, an organic emission layer on the anode electrode, a cathode electrode on the organic emission layer, an auxiliary electrode connected to the cathode electrode, a signal pad in the pad area, and a first pad electrode connected to the signal pad, the first pad electrode covering a top of the signal pad, the first pad electrode being configured to prevent the top of the signal pad from being corroded, wherein the auxiliary electrode includes a first auxiliary electrode and a second auxiliary electrode connected to the first auxiliary electrode through a contact hole, and wherein the first pad electrode includes a same material as the first auxiliary electrode.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of Korean Patent Application No.10-2015-0075397, filed on May 28, 2015, the entire disclosure of whichis hereby incorporated by reference herein for all purposes.

BACKGROUND

1. Technical Field

The present disclosure relates to an organic light-emitting displayapparatus, and, more particularly, to a top-emission type organiclight-emitting display apparatus and a method of manufacturing the same.

2. Discussion of the Related Art

Organic light-emitting display apparatuses are self-emitting apparatusesand have low power consumption, a fast response time, high emissionefficiency, high luminance, and a wide viewing angle. The organiclight-emitting display apparatuses are classified into a top-emissiontype and a bottom-emission type, based on a transmission direction oflight emitted from an organic light-emitting device. In thebottom-emission type organic light-emitting display apparatus, a circuitelement is disposed between an emission layer and an image displayingsurface, and for this reason, an aperture ratio is lowered. On the otherhand, in the top-emission type organic light-emitting display apparatus,the circuit element is not disposed between the emission layer and theimage displaying surface. Thus, an aperture ratio is enhanced.

FIG. 1 is a schematic cross-sectional view of a related art top-emissiontype organic light-emitting display apparatus.

As shown in FIG. 1, a thin film transistor (TFT) layer T that includesan active layer 11, a gate insulation layer 12, a gate electrode 13, aninterlayer dielectric 14, a source electrode 15, and a drain electrode16 is formed in an active area AA on a substrate 10. A passivation layer20 and planarization layer 30 are sequentially formed on the TFT layerT.

An anode electrode 40 and an auxiliary electrode 50 are formed on theplanarization layer 30. The auxiliary electrode 50 decreases aresistance of a cathode electrode 80, as will be described below.

A bank 60 is formed on the anode electrode 40 and the auxiliaryelectrode 50 and defines a pixel area. An organic emission layer 70 isformed in the pixel area defined by the bank 60, and the cathodeelectrode 80 is formed on the organic emission layer 70.

In the top-emission type organic light-emitting display apparatus, lightemitted from the organic emission layer 70 passes through the cathodeelectrode 80. Therefore, the cathode electrode 80 is formed of atransparent conductive material, and a resistance of the cathodeelectrode 80 increases. To decrease the resistance of the cathodeelectrode 80, the cathode electrode 80 is connected to the auxiliaryelectrode 50.

The gate insulation layer 12 and the interlayer dielectric 14 are formedin a pad area PA on the substrate 10, a signal pad 90 is formed on theinterlayer dielectric 14, and the passivation layer 20 is formed on thesignal pad 90. A hole is provided in the passivation layer 20, and thesignal pad 90 is exposed to the outside through the hole. Because thesignal pad 90 should be connected to an external driving circuit, thesignal pad 90 is exposed to the outside by forming the hole in thepassivation layer 20.

The related art top-emission type organic light-emitting displayapparatus has the following problems.

Because the signal pad 90 should be connected to the external drivingcircuit, a top of the signal pad 90 is exposed to the outside. For thisreason, the top of the signal pad 90 is corroded, and the corrosion canspread to another area. A metal layer having excellent corrosionresistance may be further formed on the top of the signal pad 90 toprevent the top of the signal pad 90 from being corroded. However, inthis case, the number of processes increases. Also, an electrode layer,which is the same as the anode electrode 40, may be formed on the signalpad 90 through the same process to prevent the top of the signal pad 90from being corroded without an increase in number of processes. Even inthis case, however, it is unable to prevent a material of the electrodematerial from being corroded, or it is unable to prevent corrosion frombeing spread through a side surface of the electrode layer.

Moreover, to connect the signal pad 90 to the external driving circuit,the top of the signal pad 90 is exposed by forming the hole in thepassivation layer 20, but when the hole of the passivation layer 20 ispreviously formed, an etchant for pattern-forming the anode electrode 40flows through the hole and damages the signal pad 90. To prevent thedamage, a process of forming the hole of the passivation layer 20 forexposing the top of the signal pad 90 may be separately performed aftera process of pattern-forming the anode electrode 40 is completed, but inthis case, a separate (additional) mask process is added.

SUMMARY

Accordingly, the present disclosure is directed to an organiclight-emitting display apparatus and a method of manufacturing the samethat substantially obviate one or more of the problems due tolimitations and disadvantages of the related art.

An object of the present disclosure is to provide a top-emission typeorganic light-emitting display apparatus and a method of manufacturingthe same, in which the number of additional processes is minimized, anda signal pad is prevented from being corroded.

Additional features and advantages will be set forth in the descriptionwhich follows, and in part will be apparent from the description, or maybe learned by practice of the invention. The objectives and otheradvantages of the disclosure will be realized and attained by thestructure particularly pointed out in the written description and claimsthereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present disclosure, as embodied and broadly described, there isprovided an organic light-emitting display apparatus, including: asubstrate including an active area and a pad area, an anode electrode inthe active area of the substrate, an organic emission layer on the anodeelectrode, a cathode electrode on the organic emission layer, anauxiliary electrode connected to the cathode electrode, a signal pad inthe pad area of the substrate, and a first pad electrode connected tothe signal pad, the first pad electrode covering a top of the signalpad, the first pad electrode being configured to prevent the top of thesignal pad from being corroded, wherein the auxiliary electrode includesa first auxiliary electrode and a second auxiliary electrode connectedto the first auxiliary electrode through a contact hole, and wherein thefirst pad electrode includes a same material as the first auxiliaryelectrode.

In another aspect, there is provided a method of manufacturing anorganic light-emitting display apparatus, the method including: forming,on a substrate: a source electrode, a drain electrode, and a signal pad,forming a passivation layer on the source electrode, the drainelectrode, and the signal pad, forming a first contact hole externallyexposing the source electrode or the drain electrode by removing apredetermined region of the passivation layer, forming a second contacthole externally exposing the signal pad by removing another partialregion of the passivation layer, forming a first anode electrodeconnected to the source electrode or the drain electrode, forming afirst auxiliary electrode separated from the first anode electrode,forming a first pad electrode connected to the signal pad, the first padelectrode being formed of a same material as the first auxiliaryelectrode, forming a third contact hole externally exposing the firstanode electrode, and forming a fourth contact hole externally exposingthe first auxiliary electrode.

Other systems, methods, features and advantages will be, or will become,apparent to one with skill in the art upon examination of the followingfigures and detailed description. It is intended that all suchadditional systems, methods, features and advantages be included withinthis description, be within the scope of the present disclosure, and beprotected by the following claims. Nothing in this section should betaken as a limitation on those claims. Further aspects and advantagesare discussed below in conjunction with the embodiments. It is to beunderstood that both the foregoing general description and the followingdetailed description of the present disclosure are examples andexplanatory, and are intended to provide further explanation of thedisclosure as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate implementations of the inventionand together with the description serve to explain the principles of theinvention.

FIG. 1 is a schematic cross-sectional view of a related art top-emissiontype organic light-emitting display apparatus.

FIG. 2 is a cross-sectional view of an organic light-emitting displayapparatus according to an example embodiment of the present disclosure.

FIG. 3 is a cross-sectional view of an organic light-emitting displayapparatus according to an example embodiment of the present disclosure.

FIGS. 4A to 4K are cross-sectional views illustrating a method ofmanufacturing an organic light-emitting display apparatus according toan example embodiment of the present disclosure.

FIGS. 5A to 5H are cross-sectional views illustrating a method ofmanufacturing an organic light-emitting display apparatus according toan example embodiment of the present disclosure.

Throughout the drawings and the detailed description, unless otherwisedescribed, the same drawing reference numerals should be understood torefer to the same elements, features, and structures. The relative sizeand depiction of these elements may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings. In the following description, when a detailed description ofwell-known functions or configurations related to this document isdetermined to unnecessarily cloud a gist of the invention, the detaileddescription thereof will be omitted. The progression of processing stepsand/or operations described is an example; however, the sequence ofsteps and/or operations is not limited to that set forth herein and maybe changed as is known in the art, with the exception of steps and/oroperations necessarily occurring in a certain order. Like referencenumerals designate like elements throughout. Names of the respectiveelements used in the following explanations are selected only forconvenience of writing the specification and may be thus different fromthose used in actual products.

In the description of embodiments, when a structure is described asbeing positioned “on or above” or “under or below” another structure,this description should be construed as including a case in which thestructures contact each other as well as a case in which a thirdstructure is disposed therebetween.

Hereinafter, example embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view of an organic light-emitting displayapparatus according to an example embodiment of the present disclosure.

As shown in FIG. 2, the organic light-emitting display apparatusaccording to an example embodiment of the present disclosure may includean active area AA and a pad area PA which are included in a substrate100. A thin film transistor (TFT) T, a passivation layer 165, a firstplanarization layer 171, a second planarization layer 172, a first anodeelectrode 180, a second anode electrode 200, a first auxiliary electrode190, a second auxiliary electrode 210, a bank 220, a partition wall 230,an organic emission layer 240, and a cathode electrode 250 may be formedin the active area AA of the substrate 100.

The TFT T may include an active layer 110, a gate insulation layer 120,a gate electrode 130, an interlayer dielectric 140, a source electrode150, and a drain electrode 160. The active layer 110 may be formed onthe substrate 100 to overlap the gate electrode 130. The active layer110 may be formed of a silicon-based semiconductor material, or may beformed of an oxide-based semiconductor material. Although not shown, alight-shielding layer may be further formed between the substrate 100and the active layer 110. For example, external light incident through abottom of the substrate 100 may be blocked by the light shielding layer,thereby preventing the active layer 110 from being damaged by theexternal light.

The gate insulation layer 120 may be formed on the active layer 110. Thegate insulation layer 120 may insulate the active layer 110 from thegate electrode 130. The gate insulation layer 120 may be formed of aninorganic insulating material, for example, silicon oxide (SiO_(x)),silicon nitride (SiN_(x)), or a multilayer thereof, but embodiments arenot limited thereto. The gate insulation layer 120 may extend to the padarea PA.

The gate electrode 130 may be formed on the gate insulation layer 120.The gate electrode 130 may be formed to overlap the active layer 110with the gate insulation layer 120 therebetween. The gate electrode 130may be formed of a single layer or a multilayer formed, for example, ofone of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au),titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu) or an alloythereof, but embodiments are not limited thereto.

The interlayer dielectric 140 may be formed on the gate electrode 130.The interlayer dielectric 140 may be formed of the same inorganicinsulating material as that of the gate insulation layer 120, forexample, silicon oxide (SiO_(x)), silicon nitride (SiN_(x)), or amultilayer thereof, but embodiments are not limited thereto. Theinterlayer dielectric 140 may extend to the pad area PA.

The source electrode 150 and the drain electrode 160 may be formed toface each other on the interlayer dielectric 140. A first contact holeCH1 exposing one end region of the active layer 110 and a second contacthole CH2 exposing the other end region of the active layer 110 may beprovided in the gate insulation layer 120 and the interlayer dielectric140. The source electrode 150 may be connected to the other end regionof the active layer 110 through the second contact hole CH2, and thedrain electrode 160 may be connected to the one end region of the activelayer 110 through the first contact hole CH1.

The source electrode 150 may include a lower source electrode 151 and anupper source electrode 152. The lower source electrode 151 may be formedbetween the interlayer dielectric 140 and the upper source electrode 152and may enhance an adhesive force between the interlayer dielectric 140and the upper source electrode 152. Also, the lower source electrode 151may protect a bottom of the upper source electrode 152, therebypreventing the bottom of the upper source electrode 152 from beingcorroded. Therefore, an oxidation rate of the lower source electrode 151may be lower than that of the upper source electrode 152. That is, thelower source electrode 151 may be formed of a material that is strongerin corrosion resistance than a material forming the upper sourceelectrode 152. As described above, the lower source electrode 151 mayact as an adhesion enhancement layer or an anti-corrosion layer and maybe formed of an alloy (MoTi) of molybdenum (Mo) and titanium (Ti), butembodiments are not limited thereto.

The upper source electrode 152 may be formed on a top of the lowersource electrode 151. The upper source electrode 152 may be formed ofcopper (Cu), which is a metal having a low resistance, but embodimentsare not limited thereto. The upper source electrode 152 may be formed ofmetal which is relatively lower in resistance than the lower sourceelectrode 151. In order to lower a total resistance of the sourceelectrode 150, a thickness of the upper source electrode 152 may beformed thicker than that of the lower source electrode 151.

Similarly to the above-described source electrode 150, the drainelectrode 160 may include a lower drain electrode 161 and an upper drainelectrode 162. The lower drain electrode 161 may be formed between theinterlayer dielectric 140 and the upper drain electrode 162. The lowerdrain electrode 161 may enhance an adhesive force between the interlayerdielectric 140 and the upper drain electrode 162, and may also prevent abottom of the upper drain electrode 162 from being corroded. Therefore,an oxidation rate of the lower drain electrode 161 may be lower thanthat of the upper drain electrode 162. That is, the lower drainelectrode 161 may be formed of a material having a stronger corrosionresistance than a material forming the upper drain electrode 162. Asdescribed above, the lower drain electrode 161 may be formed of an alloy(MoTi) of molybdenum (Mo) and titanium (Ti), similarly to theabove-described material of the lower source electrode 151, butembodiments are not limited thereto.

The upper drain electrode 162 may be formed on top of the lower drainelectrode 161 and may be formed of copper (Cu), similarly to theabove-described material of the upper source electrode 152, butembodiments are not limited thereto. The upper drain electrode 162 maybe thicker than that of the lower drain electrode 161, thereby loweringa total resistance of the drain electrode 160.

The upper drain electrode 162 may be formed of the same material as thatof the upper source electrode 152, and may have the same thickness asthat of the upper source electrode 152, and the lower drain electrode161 may be formed of the same material as that of the lower sourceelectrode 151, and may have the same thickness as that of the lowersource electrode 151. In some embodiments, the drain electrode 160 andthe source electrode 150 may be simultaneously formed through the sameprocess.

A structure of the TFT T is not limited to the illustrated structure,and may be variously modified to structures known to those skilled inthe art. For example, a top gate structure in which the gate electrode130 is formed on the active layer 110 is illustrated in the FIG. 2example, but the TFT T may alternatively be formed in a bottom gatestructure in which the gate electrode 130 is formed under the activelayer 110.

The passivation layer 165 may be formed on the TFT T, and, for example,may be formed on tops of the source electrode 150 and the drainelectrode 160. The passivation layer 165 protects the TFT T. Thepassivation layer 165 may be formed of an inorganic insulating material(for example, SiO_(x) and SiN_(x)), but embodiments are not limitedthereto. The passivation layer 165 may extend to the pad area PA.

The first planarization layer 171 may be formed on the passivation layer165. The first planarization layer 171 may planarize an upper surface ofthe substrate 100 including the TFT T. The first planarization layer 171may be formed of an organic insulating material, such as acryl resin,epoxy resin, phenolic resin, polyamide resin, polyimide resin, or thelike, but embodiments are not limited thereto. The first planarizationlayer 171 may not extend to the pad area PA.

The first anode electrode 180 and the first auxiliary electrode 190 maybe formed on the first planarization layer 171. That is, the first anodeelectrode 180 and the first auxiliary electrode 190 may be formed on thesame layer. A third contact hole CH3 exposing the source electrode 150may be provided in the passivation layer 165 and the first planarizationlayer 171, and the source electrode 150 may be connected to the firstanode electrode 180 through the third contact hole CH3. In someembodiments, the first anode electrode 180 may be connected with thesource electrode 150. However, the source electrode 150 and the drainelectrode 160 can be switched based on the mode of the transistor.Accordingly, in some embodiments, the first anode electrode 180 may beconnected with the drain electrode 160 instead of the source electrode150. As a result, the first anode electrode 180 may be connected withthe source electrode 150 or the drain electrode 160.

The first anode electrode 180 may include a first lower anode electrode181, a first upper anode electrode 182, and a first cover anodeelectrode 183. The first lower anode electrode 181 may be formed betweenthe first planarization layer 171 and the first upper anode electrode182, and may enhance an adhesive force between the first planarizationlayer 171 and the first upper anode electrode 182. Also, the first loweranode electrode 181 may protect a bottom of the first upper anodeelectrode 182, thereby preventing the bottom of the first upper anodeelectrode 182 from being corroded. Therefore, an oxidation rate of thefirst lower anode electrode 181 may be lower than that of the firstupper anode electrode 182. That is, the first lower anode electrode 181may be formed of a material having a stronger corrosion resistance thana material forming the first upper anode electrode 182. Also, the firstlower anode electrode 181 may protect a top of the upper sourceelectrode 152, thereby preventing the top of the upper source electrode152 from being corroded. Therefore, an oxidation rate of the first loweranode electrode 181 may be lower than that of the upper source electrode152. That is, the first lower anode electrode 181 may be formed of amaterial having a stronger corrosion resistance than a material formingthe upper source electrode 152. As described above, the first loweranode electrode 181 may prevent the top of the upper source electrode152 from being corroded. Thus, the source electrode 150 may be formed inthe above-described two-layer structure. The first lower anode electrode181 may act as an adhesion enhancement layer or an anti-corrosion layerand may be formed of an alloy (MoTi) of molybdenum (Mo) and titanium(Ti), but embodiments are not limited thereto.

The first upper anode electrode 182 may be formed between the firstlower anode electrode 181 and the first cover anode electrode 183. Thefirst upper anode electrode 182 may be formed of copper (Cu), which is ametal having a low resistance, but embodiments are not limited thereto.The first upper anode electrode 182 may be formed of metal which isrelatively lower in resistance than the first lower anode electrode 181.To lower a total resistance of the first anode electrode 180, the firstupper anode electrode 182 may be thicker than that of each of the firstlower anode electrode 181 and the first cover anode electrode 183.

The first cover anode electrode 183 may be formed on the first upperanode electrode 182. The first cover anode electrode 183 may be formedto cover a top and a side surface of the first upper anode electrode182, thereby preventing the first upper anode electrode 182 from beingcorroded. To this end, an oxidation rate of the first cover anodeelectrode 183 may be lower than that of the first upper anode electrode182. That is, the first cover anode electrode 183 may be formed of amaterial having a stronger corrosion resistance than a material formingthe first upper anode electrode 182.

The first cover anode electrode 183 may cover up to a side surface ofthe first lower anode electrode 181. In such a case, an oxidation rateof the first cover anode electrode 183 may be lower than that of thefirst lower anode electrode 181. That is, the first cover anodeelectrode 183 may be formed of a material having a stronger corrosionresistance than a material forming the first lower anode electrode 181.The first cover anode electrode 183 may be formed of a transparentconductive material, such as indium tin oxide (ITO) or the like, butembodiments are not limited thereto.

Similarly to the above-described first anode electrode 180, the firstauxiliary electrode 190 may include a first lower auxiliary electrode191, a first upper auxiliary electrode 192, and a first cover auxiliaryelectrode 183. The first lower auxiliary electrode 191 may be formedbetween the first planarization layer 171 and the first upper auxiliaryelectrode 192. The first lower auxiliary electrode 191 may enhance anadhesive force between the first planarization layer 171 and the firstupper auxiliary electrode 192, and may also prevent a bottom of thefirst upper auxiliary electrode 192 from being corroded. Therefore, anoxidation rate of the first lower auxiliary electrode 191 may be lowerthan that of the first upper auxiliary electrode 192. That is, the firstlower auxiliary electrode 191 may be formed of a material having astronger corrosion resistance than a material forming the first upperauxiliary electrode 192. As described above, the first lower auxiliaryelectrode 191 may be formed of an alloy (MoTi) of molybdenum (Mo) andtitanium (Ti), which is similar to the above-described material of thefirst lower anode electrode 181, but embodiments are not limitedthereto.

The first upper auxiliary electrode 192 may be formed between the firstlower auxiliary electrode 191 and the first cover auxiliary electrode193 and may be formed of copper (Cu), which similar to theabove-described material of the first upper anode electrode 182, butembodiments are not limited thereto. The first upper auxiliary electrode192 (which has a relatively low resistance) may be thicker than that ofeach of the first lower auxiliary electrode 191 and the first coverauxiliary electrode 193 (which have relatively high resistances),thereby lowering a total resistance of the first auxiliary electrode190.

The first cover auxiliary electrode 193 may be formed on the first upperauxiliary electrode 192. The first cover auxiliary electrode 193 may beformed to cover a top and a side surface of the first upper auxiliaryelectrode 192, thereby preventing the first upper auxiliary electrode192 from being corroded. To this end, an oxidation rate of the firstcover auxiliary electrode 193 may be lower than that of the first upperauxiliary electrode 192. That is, the first cover auxiliary electrode193 may be formed of a material having a stronger corrosion resistancethan a material forming the first upper auxiliary electrode 192.

The first cover auxiliary electrode 193 may cover up to a side surfaceof the first lower auxiliary electrode 191. In this case, an oxidationrate of the first cover auxiliary electrode 193 may be lower than thatof the first lower auxiliary electrode 191. That is, the first coverauxiliary electrode 193 may be formed of a material having a strongercorrosion resistance than a material forming the first lower auxiliaryelectrode 191. The first cover auxiliary electrode 193 may be formed ofa transparent conductive material, such as ITO or the like, butembodiments are not limited thereto.

The first cover auxiliary electrode 193 may be formed of the samematerial as that of the first cover anode electrode 183, and may havethe same thickness as that of the first cover anode electrode 183. Thefirst upper auxiliary electrode 192 may be formed of the same materialas that of the first upper anode electrode 182, and may have the samethickness as that of the first upper anode electrode 182. The firstlower auxiliary electrode 191 may be formed of the same material as thatof the first lower anode electrode 181, and may have the same thicknessas that of the first lower anode electrode 181. In some embodiments, thefirst auxiliary electrode 190 and the first anode electrode 180 may beformed simultaneously through the same process.

The second planarization layer 172 may be formed on the first auxiliaryelectrode 190 and the first anode electrode 180. The secondplanarization layer 172 may planarize an upper surface of the substrate100 along with the above-described first planarization layer 171. Thesecond planarization layer 172 may be formed of an organic insulatingmaterial, such as acryl resin, epoxy resin, phenolic resin, polyamideresin, polyimide resin, or the like, but embodiments are not limitedthereto. The second planarization layer 172 may not extend to the padarea PA.

A fourth contact hole CH4 and a fifth contact hole CH5 may be includedin the second planarization layer 172. The first anode electrode 180 maybe exposed by the fourth contact hole CH4, and the first auxiliaryelectrode 190 may be exposed by the fifth contact hole CH5.

The second anode electrode 200 may be formed on the second planarizationlayer 172. The second anode electrode 200 may be connected to the firstanode electrode 180 through the fourth contact hole CH4. The secondanode electrode 200 may reflect light, emitted from the organic emissionlayer 240, in an upward direction, and the second anode electrode 200may be formed of a highly reflective material.

The second anode electrode 200 may include a second lower anodeelectrode 201, a second center anode electrode 202, and a second upperanode electrode 203. The second lower anode electrode 201 may be formedbetween the first anode electrode 180 and the second center anodeelectrode 202. The second lower anode electrode 201 may protect a bottomof the second center anode electrode 202, thereby preventing the bottomof the second center anode electrode 202 from being corroded. Anoxidation rate of the second lower anode electrode 201 may be lower thanthat of the second center anode electrode 202. That is, the second loweranode electrode 201 may be formed of a material having a strongercorrosion resistance than a material forming the second center anodeelectrode 202. The second lower anode electrode 201 may be formed of atransparent conductive material, such as ITO or the like, butembodiments are not limited thereto.

The second center anode electrode 202 may be formed between the secondlower anode electrode 201 and the second upper anode electrode 203. Thesecond center anode electrode 202 may be formed of a material having alower resistance and a better reflectivity than the second lower anodeelectrode 201 and the second upper anode electrode 203. For example, thesecond center anode electrode 202 may be formed of silver (Ag). However,embodiments are not limited thereto. A thickness of the second centeranode electrode 202 (which has a relatively low resistance) may beformed thicker than that of each of the second lower anode electrode 201and the second upper anode electrode 203 (which have relatively highresistances), thereby lowering a total resistance of the second anodeelectrode 200.

The second upper anode electrode 203 may be formed on a top of thesecond center anode electrode 202, thereby preventing the top of thesecond center anode electrode 202 from being corroded. To this end, anoxidation rate of the second upper anode electrode 203 may be lower thanthat of the second center anode electrode 202. That is, the second upperanode electrode 203 may be formed of a material having a strongercorrosion resistance than a material forming the second center anodeelectrode 202. The second upper anode electrode 203 may be formed of atransparent conductive material, such as ITO or the like, butembodiments are not limited thereto.

The second auxiliary electrode 210 may be formed on the secondplanarization layer 172 identically to the second anode electrode 200.The second auxiliary electrode 210 may be connected to the firstauxiliary electrode 190 through the fifth contact hole CH5. The secondauxiliary electrode 210 may lower a resistance of the cathode electrode250 along with the first auxiliary electrode 190.

The second auxiliary electrode 210 may include a second lower auxiliaryelectrode 211, a second center auxiliary electrode 212, and a secondupper auxiliary electrode 213. The second lower auxiliary electrode 211may be formed between the first auxiliary electrode 190 and the secondcenter auxiliary electrode 212. The second lower auxiliary electrode 211may protect a bottom of the second center auxiliary electrode 212,thereby preventing the bottom of the second center auxiliary electrode212 from being corroded. To this end, an oxidation rate of the secondlower auxiliary electrode 211 may be lower than that of the secondcenter auxiliary electrode 212. That is, the second lower auxiliaryelectrode 211 may be formed of a material having a stronger corrosionresistance than a material forming the second center auxiliary electrode212. The second lower auxiliary electrode 211 may be formed of atransparent conductive material, such as ITO or the like, butembodiments are not limited thereto.

The second center auxiliary electrode 212 may be formed between thesecond lower auxiliary electrode 211 and the second upper auxiliaryelectrode 213. The second center auxiliary electrode 212 may be formedof a material which having a lower resistance and a better reflectivitythan the second lower auxiliary electrode 211 and the second upperauxiliary electrode 213, and for example, may be formed of silver (Ag).However, the present embodiment is not limited thereto. A thickness ofthe second center auxiliary electrode 212 which is relatively low inresistance may be formed thicker than that of each of the second lowerauxiliary electrode 211 and the second upper auxiliary electrode 213which are relatively high in resistance, thereby lowering a totalresistance of the second auxiliary electrode 210.

The second upper auxiliary electrode 213 may be formed on a top of thesecond center auxiliary electrode 212, thereby preventing the top of thesecond center auxiliary electrode 212 from being corroded. To this end,an oxidation rate of the second upper auxiliary electrode 213 may belower than that of the second center auxiliary electrode 212. That is,the second upper auxiliary electrode 213 may be formed of a materialhaving a stronger corrosion resistance than a material forming thesecond center auxiliary electrode 212. The second upper auxiliaryelectrode 213 may be formed of a transparent conductive material, suchas ITO or the like, but embodiments are not limited thereto.

The second upper auxiliary electrode 213 may be formed of the samematerial as that of the second upper anode electrode 203, and may havethe same thickness as that of the second upper anode electrode 203. Thesecond center auxiliary electrode 212 may be formed of the same materialas that of the second center anode electrode 202, and may have the samethickness as that of the second center anode electrode 202. The secondlower auxiliary electrode 211 may be formed of the same material as thatof the second lower anode electrode 201, and may have the same thicknessas that of the second lower anode electrode 201. In some embodiments,the second auxiliary electrode 210 and the second anode electrode 200may be simultaneously formed through the same process.

According to an embodiment of the present disclosure, two auxiliaryelectrodes (for example, the first and second auxiliary electrodes 190and 210) connected to each other may be formed for lowering theresistance of the cathode electrode 250. Thus, the desired resistancecharacteristic of an auxiliary electrode may be more easily adjusted.

Because the second auxiliary electrode 210 may be formed on the samelayer as a layer on which the second anode electrode 200 is disposed, awidth of the second anode electrode 200 may be reduced when a width ofthe second auxiliary electrode 210 increases. In this case, a pixel areaof a display apparatus may be reduced. As such, there may be alimitation in increasing the width of the second auxiliary electrode210. Therefore, according to an embodiment of the present disclosure,the first auxiliary electrode 190 connected to the second auxiliaryelectrode 210 may be further formed under the second auxiliary electrode210. Thus, the resistance of the cathode electrode 150 may beeffectively lowered, even without any reduction in a pixel area.

The first auxiliary electrode 190 may be formed on the same layer as alayer on which the first anode electrode 180 is disposed. Because thefirst anode electrode 180 may connect the source electrode 150 to thesecond anode electrode 200, a width of the first anode electrode 180 maybe reduced, thereby increasing a width of the first auxiliary electrode190. That is, the width of the first auxiliary electrode 190 may beformed greater than that of the first anode electrode 180. In addition,the width of first auxiliary electrode 190 may increase so the firstauxiliary electrode 190 may overlap the second anode electrode 200,whereby the resistance of the cathode electrode 150 may be moreeffectively lowered.

The bank 220 may be formed on the second anode electrode 200 and thesecond auxiliary electrode 210. The bank 220 may be formed on one sideand the other side (e.g., both sides) of the second anode electrode 200to expose a top of the second anode electrode 200. Because the bank 220may be formed to expose the top of the second anode electrode 200, anarea where an image is displayed may be secured. Also, because the bank220 may be formed on the one side and the other side of the second anodeelectrode 200, a side surface of the second center anode electrode 202vulnerable to corrosion may be prevented from being exposed to theoutside, thereby preventing the side surface of the second center anodeelectrode 202 from being corroded.

The bank 220 may be formed on one side and the other side (e.g., on bothsides) of the second auxiliary electrode 210 to expose a top of thesecond auxiliary electrode 210. Because the bank 220 may be formed toexpose the top of the second auxiliary electrode 210, an electricalconnection space between the second auxiliary electrode 210 and thecathode electrode 250 may be secured. Also, because the bank 220 may beformed on the one side and the other side of the second auxiliaryelectrode 210, a side surface of the second center auxiliary electrode212 vulnerable to corrosion may be prevented from being exposed to theoutside, thereby preventing the side surface of the second centerauxiliary electrode 212 from being corroded.

Moreover, the bank 220 may be formed between the second anode electrode200 and the second auxiliary electrode 210, and may insulate the secondanode electrode 200 from the second auxiliary electrode 210. The bank220 may be formed of an organic insulating material, such as polyimideresin, acryl resin, benzocyclobutene (BCB), or the like, but embodimentsare not limited thereto.

The partition wall 230 may be formed on the second auxiliary electrode210. The partition wall 230 may be separated from the bank 220 by acertain distance, and the second auxiliary electrode 210 may beelectrically connected to the cathode electrode 250 through a separationspace between the partition wall 230 and the bank 220. The secondauxiliary electrode 210 may be electrically connected to the cathodeelectrode 250 without forming the partition wall 230. However, if thepartition wall 230 is formed, the organic emission layer 240 may be moreeasily deposition-formed. The formation of the partition wall 230 willbe described below in more detail.

If the partition wall 230 is not formed, a mask pattern that covers atop of the second auxiliary electrode 210 may be used in depositing theorganic emission layer 240, so that the top of the second auxiliaryelectrode 210 may not be covered by the organic emission layer 240.However, if the partition wall 230 is formed, a top of the partitionwall 230 may act as an eaves shape or overhang in depositing the organicemission layer 240. Thus, because the organic emission layer 240 may notbe deposited under the eaves, the mask pattern which covers the top ofthe second auxiliary electrode 210 may not be needed. That is, in afront view of an example of the organic light-emitting displayapparatus, when the top of the partition wall 230 that acts as eaves isformed to cover a separation space between the partition wall 230 andthe bank 220, the organic emission layer 240 may not penetrate into theseparation space between the partition wall 230 and the bank 220. Thus,the second auxiliary electrode 210 may be exposed in the separationspace between the partition wall 230 and the bank 220. For example, theorganic emission layer 240 may be formed by a deposition process, suchas an evaporation process, which may be excellent in terms of accuracyand straightness of deposition of a deposited material. However,embodiments are not limited thereto. Thus, the organic emission layer240 may not be deposited in the separation space between the partitionwall 230 and the bank 220.

As described above, a width of the top of the partition wall 230 may begreater than that of a bottom of the partition wall 230, such that thetop of the partition wall 230 may act as the eaves. The partition wall230 may include a lower first partition wall 231 and an upper secondpartition wall 232. The first partition wall 231 may be formed on a topof the second auxiliary electrode 210, and may be formed of the samematerial as that of the bank 220, may be formed through the same processas that of the bank 220. The second partition wall 232 may be formed ona top of the first partition wall 231. A width of a top of the secondpartition wall 232 may be formed greater than that of a bottom of thesecond partition wall 232. For example, the top of the second partitionwall 232 may be formed to cover the separation space between thepartition wall 230 and the bank 220, and may act as eaves.

The organic emission layer 240 may be formed on the second anodeelectrode 200. The organic emission layer 240 may include a holeinjection layer, a hole transport layer, an emission layer, an electrontransport layer, and an electron injection layer. The organic emissionlayer 240 may be modified to have various structures known to thoseskilled in the art.

The organic emission layer 240 may extend to the top of the bank 220.However, the organic emission layer 240 may not extend to the top of thesecond auxiliary electrode 210 to cover the top of the second auxiliaryelectrode 210. This is because, if the organic emission layer 240 coversthe top of the second auxiliary electrode 210, it may be difficult toelectrically connect the second auxiliary electrode 210 to the cathodeelectrode 250. As described above, the organic emission layer 240 may beformed by a deposition process without a mask that covers the top of thesecond auxiliary electrode 210. For example, the organic emission layer240 may be formed on the top of the partition wall 230.

The cathode electrode 250 may be formed on the organic emission layer240. The cathode electrode 250 may be formed on a surface from whichlight is emitted, and thus may be formed of a transparent conductivematerial. Because the cathode electrode 250 may be formed of atransparent conductive material, a resistance of the cathode electrode250 may be high. For example, in order to lower the resistance of thecathode electrode 250, the cathode electrode 250 may be connected to thesecond auxiliary electrode 210. Also, the cathode electrode 250 may beconnected to the second auxiliary electrode 210 through the separationspace between the partition wall 230 and the bank 220. The cathodeelectrode 250 may be formed by a deposition process, such as asputtering process, which may not be as accurate or provide as muchstraightness of deposition of a deposited material. However, embodimentsare not limited thereto. Thus, the cathode electrode 250 may bedeposited in the separation space between the partition wall 230 and thebank 220 in a process of depositing the cathode electrode 250.

Although not shown, an encapsulation layer may be further formed on thecathode electrode 250, and may prevent penetration of water. Theencapsulation layer may use various materials known to those skilled inthe art. Also, although not shown, a color filter may be further formedfor each pixel and on the cathode electrode 250. For example, whitelight may be emitted from the organic emission layer 240.

The gate insulation layer 120, the interlayer dielectric 140, the signalpad 300, the passivation layer 165, and a first pad electrode 400 may beformed in the pad area PA of the substrate 100. The gate insulationlayer 120 may be formed on the substrate 100, and the interlayerdielectric 140 may be formed on the gate insulation layer 120. The gateinsulation layer 120 and the interlayer dielectric 140 may extend fromthe active area AA and may be formed all over the pad area PA.

The signal pad 300 may be formed on the interlayer dielectric 140. Thesignal pad 300 may be formed on the same layer as a layer where thesource electrode 150 and the drain electrode 160 in the active area AAare disposed.

The signal pad 300 may include a lower signal pad 301 and an uppersignal pad 302. The lower signal pad 301 may be formed between theinterlayer dielectric 140 and the upper signal pad 302, and may enhancean adhesive force between the interlayer dielectric 140 and the uppersignal pad 302. Also, the lower signal pad 301 may prevent a bottom ofthe upper signal pad 302 from being corroded. Therefore, an oxidationrate of the lower signal pad 301 may be lower than that of the uppersignal pad 302. That is, the lower signal pad 301 may be formed of amaterial having a stronger corrosion resistance than a material formingthe upper signal pad 302. As described above, the lower signal pad 301may be formed of an alloy (MoTi) of molybdenum (Mo) and titanium (Ti),which may be similar to the above-described material of the lower sourceelectrode 151 or the lower drain electrode 161, but embodiments are notlimited thereto.

The upper signal pad 302 may be formed on a top of the lower signal pad301. The upper signal pad 302 may be formed of copper (Cu), which ismetal having a low resistance, but embodiments are not limited thereto.The upper signal pad 302 may be formed of metal which is relativelylower in resistance than the lower signal pad 301. To lower a totalresistance of the signal pad 300, the upper signal pad 302 may bethicker than the lower signal pad 301.

The upper signal pad 302 may be formed of the same material as that ofthe upper source electrode 152 and/or the upper drain electrode 162, andmay have the same thickness as that of the upper source electrode 152and/or the upper drain electrode 162. The lower signal pad 301 may beformed of the same material as that of the lower source electrode 151and/or the lower drain electrode 161, and may have the same thickness asthat of the lower source electrode 151 and/or the lower drain electrode161. For example, the signal pad 300 and the source electrode 150; thesignal pad 300 and the drain electrode 160; or the signal pad 300, thesource electrode 150, and the drain electrode 160 may be formedsimultaneously through the same process.

The passivation layer 165 may be formed on the signal pad 300. Thepassivation layer 165 may extend from the active area AA. A sixthcontact hole CH6 exposing a portion of the signal pad 300 may beincluded in the passivation layer 165. The first pad electrode 400 maybe formed on the passivation layer 165. The first pad electrode 400 maybe connected to the signal pad 300 through the sixth contact hole CH6.The first pad electrode 400 may be exposed to the outside and connectedto an external driver.

The first pad electrode 400 may protect a top of the signal pad 300. Thetop of the signal pad 300 may be configured by the upper signal pad 302which is relatively vulnerable to corrosion. Thus, the first padelectrode 400 may be formed to cover the top of the upper signal pad 302exposed through the sixth contact hole CH6, thereby preventing the uppersignal pad 302 from being corroded. As described above, because thefirst pad electrode 400 may prevent the top of the upper signal pad 302from being corroded, the signal pad 300 may be formed in theabove-described two-layer structure. An oxidation rate of the first padelectrode 400, e.g., an oxidation rate of the first cover pad electrode403, may be lower than that of the upper signal pad 302. That is, thefirst pad electrode 400, e.g., the first cover pad electrode 403, may beformed of a material having a stronger corrosion resistance than amaterial forming the upper signal pad 302. Also, because the first padelectrode 400 may be exposed to the outside, the first cover padelectrode 403 corresponding to an uppermost surface of the first padelectrode 400 may be formed of a material having a strong corrosionresistance.

The first pad electrode 400 may be formed of the same material as thatof the first anode electrode 180 and/or the first auxiliary electrode190, and may have the same thickness as that of the first anodeelectrode 180 and/or the first auxiliary electrode 190. In someembodiments, the first pad electrode 400 and the first anode electrode180 and/or the first auxiliary electrode 190 may be pattern-formedthrough the same mask process. The first pad electrode 400 may include afirst lower pad electrode 401, a first upper pad electrode 402, and afirst cover pad electrode 403.

The first lower pad electrode 401 may be formed to cover a top of theupper signal pad 302 through the sixth contact hole CH6, therebypreventing the upper signal pad 302 from being corroded. To this end, anoxidation rate of the first lower pad electrode 401 may be lower thanthat of the upper signal pad 302. That is, the first lower pad electrode401 may be formed of a material having a stronger corrosion resistancethan a material forming the upper signal pad 302. As described above,the first lower pad electrode 401 may prevent the top of the uppersignal pad 302 from being corroded. Thus, the signal pad 300 may beformed in the above-described two-layer structure. The first lower padelectrode 401 may be formed of an alloy (MoTi) of molybdenum (Mo) andtitanium (Ti), which may be similar to the above-described material ofthe first lower anode electrode 181 and/or the first lower auxiliaryelectrode 191, but embodiments are not limited thereto. The first lowerpad electrode 401 may be formed of the same material as that of thefirst lower anode electrode 181 and/or the first lower auxiliaryelectrode 191, and may have the same thickness as that of the firstlower anode electrode 181 and/or the first lower auxiliary electrode191. For example, the first lower pad electrode 401 and the first loweranode electrode 181; the first lower pad electrode 401 and the firstlower auxiliary electrode 191; or the first lower pad electrode 401, thefirst lower anode electrode 181, and the first lower auxiliary electrode191 may be pattern-formed through the same mask process.

The first upper pad electrode 402 may be formed between the first lowerpad electrode 401 and the first cover pad electrode 403. The first upperpad electrode 402 may be formed of copper (Cu), which is a metal havinga low resistance, but embodiments are not limited thereto. The firstupper pad electrode 402 may be formed of a metal that is relativelylower in resistance than the first lower pad electrode 401 and the firstcover pad electrode 403. To lower a total resistance of the first padelectrode 400, the first upper pad electrode 402 may be thicker thaneach of the first lower pad electrode 401 and the first cover padelectrode 403. The first upper pad electrode 402 may be formed of thesame material as that of the first upper anode electrode 182 and/or thefirst upper auxiliary electrode 192 to have the same thickness as thatof the first upper anode electrode 182 and/or the first upper auxiliaryelectrode 192. For example, the first upper pad electrode 402 and thefirst upper anode electrode 182; the first upper pad electrode 402 andthe first upper auxiliary electrode 192; or the first upper padelectrode 402, the first upper anode electrode 182, and the first upperauxiliary electrode 192 may be pattern-formed through the same maskprocess.

The first cover pad electrode 403 may be formed on the first upper padelectrode 402. The first cover pad electrode 403 may be formed to covera top and a side surface of the first upper pad electrode 402, therebypreventing the first upper pad electrode 402 from being corroded. Thatis, the first cover pad electrode 403 may prevent the first upper padelectrode 402 from being exposed to the outside. An oxidation rate ofthe first cover pad electrode 403 may be lower than that of the firstupper pad electrode 402. That is, the first cover pad electrode 403 maybe formed of a material having a stronger corrosion resistance than amaterial forming the first upper pad electrode 402.

The first cover pad electrode 403 may cover up to a side surface of thefirst lower pad electrode 401. An oxidation rate of the first cover padelectrode 403 may be lower than that of the first lower pad electrode401. That is, the first cover pad electrode 403 may be formed of amaterial having a stronger corrosion resistance than a material formingthe first lower pad electrode 401. The first cover pad electrode 403 maybe formed of a transparent conductive material, such as ITO or the like,but embodiments are not limited thereto. The first cover pad electrode403 may be formed of the same material as that of the first cover anodeelectrode 183 and/or the first cover auxiliary electrode 193, and mayhave the same thickness as that of the first cover anode electrode 183and/or the first cover auxiliary electrode 193. For example, the firstcover pad electrode 403 and the first cover anode electrode 183; thefirst cover pad electrode 403 and the first cover auxiliary electrode193; or the first cover pad electrode 403, the first cover anodeelectrode 183, and the first cover auxiliary electrode 193 may bepattern-formed through the same mask process.

FIG. 3 is a cross-sectional view of an organic light-emitting displayapparatus according to an example embodiment of the present disclosure.The organic light-emitting display apparatus of FIG. 3 is the similar tothe above-described organic light-emitting display apparatus of FIG. 2,except that structures of a second anode electrode 200 and a secondauxiliary electrode 210 are changed and a second pad electrode 500 isfurther provided. Thus, like reference numerals refer to like elements.Hereinafter, elements different from the above-described elements ofFIG. 2 will be described in detail.

As shown in FIG. 3, according to an embodiment of the presentdisclosure, the second anode electrode 200 may include a second centeranode electrode 202 and a second upper anode electrode 203, and thesecond lower anode electrode 201 of the FIG. 2 example may be omitted.Also, the second auxiliary electrode 210 may include a second centerauxiliary electrode 212 and a second upper auxiliary electrode 213, andthe second lower auxiliary electrode 211 of the FIG. 2 example mayomitted.

In such a structure, the second center anode electrode 202 and thesecond center auxiliary electrode 212 may be formed of a material, suchas an alloy (MoTi) of molybdenum (Mo) and titanium (Ti), which are goodin reflectivity and are good in corrosion resistance, but embodimentsare not limited thereto.

According to an embodiment of the present disclosure, the second padelectrode 500 may be further formed on the first pad electrode 400.Because the second pad electrode 500 is further provided, a height of apad part may increase, and a contact area may increase, whereby thesecond pad electrode 500 may be more easily connected to an externaldriver. The second pad electrode 500 may be formed of the same materialas that of the second anode electrode 200 and/or the second auxiliaryelectrode 210 having a two-layer structure, and may have the samethickness as that of the second anode electrode 200 and/or the secondauxiliary electrode 210. For example, the second pad electrode 500 andthe second anode electrode 200; the second pad electrode 500 and thesecond auxiliary electrode 210; or the second pad electrode 500, thesecond anode electrode 200, and the second auxiliary electrode 210 maybe pattern-formed through the same mask process.

The second pad electrode 500 may include a second center pad electrode502 and a second upper pad electrode 503. The second center padelectrode 502 may be formed of the same material as that of the secondcenter anode electrode 202 and/or the second center auxiliary electrode212. The second upper pad electrode 503 may be formed of the samematerial as that of the second upper anode electrode 203 and/or thesecond upper auxiliary electrode 213.

According to an embodiment, a side surface of the second center padelectrode 502 may be exposed to the outside, but because the secondcenter pad electrode 502 may be formed of a material which has goodcorrosion resistance, the second center pad electrode 502 may beprevented from being corroded. Also, the second upper pad electrode 503may be exposed to the outside, but because the second upper padelectrode 503 may be formed of a material which is good in corrosionresistance, the second upper pad electrode 503 may be prevented frombeing corroded.

FIGS. 4A to 4K are cross-sectional views illustrating a method ofmanufacturing an organic light-emitting display apparatus according toan example embodiment of the present disclosure. The FIGS. 4A to 4Kexamples illustrate a method of manufacturing the above-describedorganic light-emitting display apparatus of the example of FIG. 2. Thus,like reference numerals refer to like elements, and in a material and astructure of each element, the same or similar descriptions may not berepeated.

First, as shown in FIG. 4A, an active layer 110, a gate insulation layer120, a gate electrode 130, an interlayer dielectric 140, a sourceelectrode 150, a drain electrode 160, and a signal pad 300 may besequentially formed on a substrate 100.

The active layer 110 may be formed on the substrate 100, the gateinsulation layer 120 may be formed on the active layer 110, the gateelectrode 130 may be formed on the gate insulation layer 120, theinterlayer dielectric 140 may be formed on the gate electrode 130, and afirst contact hole CH1 and a second contact hole CH2 may be formed inthe gate insulation layer 120 and the interlayer dielectric 140.Subsequently, the drain electrode 160 (which may be connected to one endregion of the active layer 110 through the first contact hole CH1), thesource electrode 150 (which may be connected to the other end region ofthe active layer 110 through the second contact hole CH2), and thesignal pad 300 may be formed.

Here, the active layer 110, the gate electrode 130, the source electrode150, and the drain electrode 160 may be formed in an active area AA. Thegate insulation layer 120 and the interlayer dielectric 140 may beformed to extend from the active area AA to a pad area PA. The signalpad 300 may be formed in the pad area AA. As such, a TFT T may be formedin the active area AA, and the signal pad 300 may be formed in the padarea PA.

The source electrode 150 may include a lower source electrode 151 and anupper source electrode 152. The drain electrode 160 may include a lowerdrain electrode 161 and an upper drain electrode 162. The signal pad 300may include a lower signal pad 301 and an upper signal pad 302. Thesource electrode 150, the drain electrode 160, and the signal pad 300may be formed simultaneously of the same material by the same patterningprocess.

Subsequently, as shown in FIG. 4B, a passivation layer 165 may be formedon the source electrode 150, the drain electrode 160, and the signal pad300; and a first planarization layer 171 may be formed on thepassivation layer 165. The passivation layer 165 may be formed to extendfrom the active area AA to the pad area PA, and the first planarizationlayer 171 may be formed in the active area AA.

The passivation layer 165 and the first planarization layer 171 may beformed to include a third contact hole CH3 in the active area AA, andthe source electrode 150 may be exposed to the outside through the thirdcontact hole CH3. Also, the passivation layer 165 may be formed toinclude a sixth contact hole CH6 in the pad area PA, and the signal pad300 may be exposed to the outside through the sixth contact hole CH6.

According to an embodiment of the present disclosure, the third contacthole CH3 for externally exposing the source electrode 150 and the sixthcontact hole CH6 for externally exposing the signal pad 300 may beformed simultaneously. Thus, the third contact hole CH3 and the sixthcontact hole CH6 may be formed through one mask process, therebypreventing the number of mask processes from increasing. Because theupper signal pad 302 exposed by the sixth contact hole CH6 may bevulnerable to corrosion, an etchant may not be brought in contact withthe upper signal pad 302. According to an embodiment of the presentdisclosure, the exposed upper signal pad 302 may be covered by a lowerpad electrode 401 in a process of FIG. 4C described below. Thus, theetchant may not be brought in contact with the upper signal pad 302. Forthe same reason, the sixth contact CH6 and the third contact hole CH3may be simultaneously formed.

Subsequently, as shown in FIG. 4C, a first anode electrode 180 and afirst auxiliary electrode 190 may be formed to be separated from eachother on the first planarization layer 171 in the active area AA. Afirst pad electrode 400 may be formed on the passivation layer 165 inthe pad area PA.

The first anode electrode 180 may be formed to be connected to thesource electrode 150 through the third contact hole CH3. The first padelectrode 400 may be formed to be connected to the signal pad 300through the sixth contact hole CH6. In some embodiments, the first anodeelectrode 180 may be formed to be connected to the drain electrode 160through the third contact hole CH3 that is formed to expose the drainelectrode 160.

The first anode electrode 180 may be configured with a first lower anodeelectrode 181, a first upper anode electrode 182, and a first coveranode electrode 183. The first auxiliary electrode 190 may be configuredwith a first lower auxiliary electrode 191, a first upper auxiliaryelectrode 192, and a first cover auxiliary electrode 193. The first padelectrode 400 may be configured with a first lower pad electrode 401, afirst upper pad electrode 402, and a first cover pad electrode 403. Thefirst anode electrode 180, the first auxiliary electrode 190, and thefirst pad electrode 400 may be simultaneously formed of the samematerial through the same patterning process.

Subsequently, as shown in FIG. 4D, a second planarization layer 172 maybe formed on a first anode electrode 180 and a first auxiliary electrode190 in the active area AA. The second planarization layer 173 may beformed to include a fourth contact hole CH4 and a fifth contact holeCH5. The first anode electrode 180 may be exposed to the outside throughthe fourth contact hole CH4. The first auxiliary electrode 190 may beexposed to the outside through the fifth contact hole CH5.

Subsequently, as shown in FIG. 4E, the first photoresist pattern 610 maybe formed on the first pad electrode 400 in the pad area PA. The firstpad electrode 400 may be covered by the first photoresist pattern 610,and thus may not be exposed to the outside. The first photoresistpattern 610 may not be formed in the active area AA.

Subsequently, as shown in FIG. 4F, an electrode layer for a second anodeelectrode (labeled as 200 in FIG. 4G) and a second auxiliary electrode(labeled as 210 in FIG. 4G) may be formed in the pad area PA and theactive area AA. In more detail, a lower electrode layer 1, anintermediate electrode layer 2, and an upper electrode layer 3 may besequentially formed on the first photoresist pattern 610 in the pad areaPA and the second planarization layer 172 in the active area AA. Also, asecond photoresist pattern 620 may be formed on the electrode layer,e.g., the upper electrode layer 3 in the active area AA.

Subsequently, as shown in FIG. 4G, a second anode electrode 200 and asecond auxiliary electrode 210 may be formed by etching the lowerelectrode layer 1, the intermediate electrode layer 2, and the upperelectrode layer 3 with the second photoresist pattern 620 as a mask.That is, the second photoresist pattern 620 may be formed as a patterncorresponding to a pattern of each of the second anode electrode 200 andthe second auxiliary electrode 210. Therefore, a portion of the lowerelectrode layer 1, a portion of the intermediate electrode layer 2, anda portion of the upper electrode layer 3 that are not covered by thesecond photoresist pattern 620 may be removed by the etching process,and portions covered by the second photoresist pattern 620 may remain,thereby forming the pattern of each of the second anode electrode 200and the second auxiliary electrode 210. As a result, the second anodeelectrode 200 and the second auxiliary electrode 210 may besimultaneously formed of the same material through the same patterningprocess.

The second anode electrode 200 may include a second lower anodeelectrode 201, a second center anode electrode 202, and a second upperanode electrode 203. The second auxiliary electrode 210 may include asecond lower auxiliary electrode 211, a second center auxiliaryelectrode 212, and a second upper auxiliary electrode 213.

When the portion of the lower electrode layer 1, the portion of theintermediate electrode layer 2, and the portion of the upper electrodelayer 3 that are not covered by the second photoresist pattern 620 areremoved by the etching process, the first pad electrode 400 may not bedamaged by an etchant because the first photoresist pattern 610 coversthe first pad electrode 400.

Subsequently, as shown in FIG. 4H, the first photoresist pattern 610 andthe second photoresist pattern 620 may be removed by a strip process.Therefore, the pad electrode 400, the second anode electrode 200, andthe second auxiliary electrode 210 may be exposed to the outside.

FIGS. 4E to 4H illustrate to a method of forming the second anodeelectrode 200 and the second auxiliary electrode 210 without the firstpad electrode 400 being damaged. According to an embodiment of thepresent disclosure, the first photoresist pattern 610 may be formed onthe first pad electrode 400 to cover the first pad electrode 400. Thus,the first pad electrode 400 may not be damaged by an etchant in formingthe pattern of each of the second anode electrode 200 and the secondauxiliary electrode 210. Also, because the first photoresist pattern 610may be removed simultaneously with the second photoresist pattern 620, amanufacturing process may be simplified.

Instead of using the first photoresist pattern 610, the secondplanarization layer 172 may be formed to cover the first pad electrode400 by extending the second planarization layer 172 to the pad area PA.Then, the second anode electrode 200 and the second auxiliary electrode210 may be formed, in the above-described process of FIG. 4D. However,in one example, a process of removing a region of the secondplanarization layer 172 extending to the pad area PA through an oxygen(O₂) ashing process may be further performed after the second anodeelectrode 200 and the second auxiliary electrode 210 are formed toexternally expose the first pad electrode 400. For example, aphotoresist pattern may be further formed as a mask for the process ofremoving the region of the second planarization layer 172 extending tothe pad area PA. Moreover, due to the oxygen (O₂) ashing process, theinside of a chamber may be contaminated, and a process time mayincrease. Therefore, as described above with reference to the examplesof FIGS. 4E to 4H, the first photoresist pattern 610 may be used.

Subsequently, as shown in FIG. 4I, a bank 220 may be formed on bothsides of the second anode electrode 200 to expose a top of the secondanode electrode 200. Also, the bank 220 may be formed on both sides ofthe second auxiliary electrode 210 to expose a top of the secondauxiliary electrode 210.

Moreover, a first partition wall 231 and a second partition wall 232 maybe sequentially formed on the exposed top of the second auxiliaryelectrode 210. The first partition wall 231 may be formed of the samematerial as that of the bank 220, which may be through the same patternforming process as that of the bank 220, and may be formedsimultaneously with the bank 220. The partition wall 230 may be formedto be separated from the bank 220 by a certain (e.g., predetermined)distance. Thus, a separation space may be provided between the partitionwall 230 and the bank 220.

For a top of the partition wall 230 to act as eaves, a width of a top ofthe second partition wall 232 may be formed greater than that of abottom of the second partition wall 232. For example, with respect to afront view of the organic light-emitting display apparatus, the top ofthe second partition wall 232 may cover the separation space between thepartition wall 230 and the bank 220. Thus, in a below-described processof depositing an organic emission layer 240, the organic emission layer240 may not be deposited in the separation space between the partitionwall 230 and the bank 220.

Subsequently, as shown in FIG. 4J, the organic emission layer 240 may beformed on the second anode electrode 200. The organic emission layer 240may be formed by a deposition process, such as an evaporation process,which may be excellent in terms of accuracy and straightness ofdeposition of a deposited material. However, embodiments are not limitedthereto. Thus, the organic emission layer 240 may be deposited on top ofthe bank 220 and the partition wall 230, but the organic emission layer240 may not be deposited in the separation space between the partitionwall 230 and the bank 220. That is, the top of the partition wall 230may act as the eaves in depositing the organic emission layer 240. Thus,even when the organic emission layer 240 is deposited without a maskpattern that covers the top of the second auxiliary electrode 210, theorganic emission layer 240 may not be deposited in the separation spacebetween the partition wall 230 and the bank 220.

Subsequently, as shown in FIG. 4K, a cathode electrode 250 may be formedon the organic emission layer 240. The cathode electrode 250 may beformed to be connected to the second auxiliary electrode 210 through theseparation space between the partition wall 230 and the bank 220. Thecathode electrode 250 may be formed by a deposition process, which maynot be as accurate or provide as much straightness of deposition of adeposited material. However, embodiments are not limited thereto. Thus,the cathode electrode 250 may be deposited in the separation spacebetween the partition wall 230 and the bank 220 in a process ofdepositing the cathode electrode 250.

FIGS. 5A to 5H are cross-sectional views illustrating a method ofmanufacturing an organic light-emitting display apparatus according toan example embodiment of the present disclosure. FIGS. 5A to 5Hillustrate examples of a method of manufacturing the above-describedorganic light-emitting display apparatus of FIG. 3. Thus, like referencenumerals refer to like elements, and in a material and a structure ofeach element, the same or similar descriptions may not be repeated.

First, as shown in FIG. 5A, an active layer 110, a gate insulation layer120, a gate electrode 130, an interlayer dielectric 140, a sourceelectrode 150, a drain electrode 160, and a signal pad 300 may besequentially formed on a substrate 100. Therefore, a TFT T may be formedin the active area AA, and the signal pad 300 may be formed in the padarea PA. Such a process is similar to the above-described process ofFIG. 4A.

Subsequently, as shown in FIG. 5B, a passivation layer 165 may be formedon the source electrode 150, the drain electrode 160, and the signal pad300. A first planarization layer 171 may be formed on the passivationlayer 165. The passivation layer 165 and the first planarization layer171 may be formed to include a third contact hole CH3 in the active areaAA. The source electrode 150 may be exposed to the outside through thethird contact hole CH3. Also, the passivation layer 165 may be formed toinclude a sixth contact hole CH6 in the pad area PA, and the signal pad300 may be exposed to the outside through the sixth contact hole CH6.Such a process is similar to the above-described process of FIG. 4B.

Subsequently, as shown in FIG. 5C, a first anode electrode 180 and afirst auxiliary electrode 190 may be formed on the first planarizationlayer 171 in the active area AA, and a first pad electrode 400 may beformed on the passivation layer 165 in the pad area PA. The first anodeelectrode 180 may be formed to be connected to the source electrode 150through the third contact hole CH3, and the first pad electrode 400 maybe formed to be connected to the signal pad 300 through the sixthcontact hole CH6. Such a process is similar to the above-describedprocess of FIG. 4C.

Subsequently, as shown in FIG. 5D, a second planarization layer 172 maybe formed on the first anode electrode 180 and the first auxiliaryelectrode 190 in the active area AA. The second planarization layer 173may be formed to include a fourth contact hole CH4 and a fifth contacthole CH5, the first anode electrode 180 may be exposed to the outsidethrough the fourth contact hole CH4, and the first auxiliary electrode190 may be exposed to the outside through the fifth contact hole CH5.Such a process is similar to the above-described process of FIG. 4D.

Subsequently, as shown in FIG. 5E, a second anode electrode 200 and asecond auxiliary electrode 210 may be formed on the second planarizationlayer 172 in the active area AA, and a second pad electrode 500 may beformed on the first pad electrode 400 in the pad area PA. The secondanode electrode 200 may be connected to the first anode electrode 180through the fourth contact hole CH4, the second auxiliary electrode 210may be connected to the second anode electrode 190 through the fifthcontact hole CH5, and the second pad electrode 500 may be formeddirectly on a top of the first pad electrode 400.

The second anode electrode 200 may include a second center anodeelectrode 202 and a second upper anode electrode 203. The secondauxiliary electrode 210 may include a second center auxiliary electrode212 and a second upper auxiliary electrode 213. The second pad electrode500 may include a second center pad electrode 502 and a second upper padelectrode 503. The second anode electrode 200, the second auxiliaryelectrode 210, and the second pad electrode 500 may be simultaneouslyformed of the same material through the same patterning process. Thus,an additional mask process is not necessary.

A first cover pad electrode 403 formed on an uppermost surface of thefirst pad electrode 400 may be formed of the same material (for example,ITO, which has good corrosion resistance) as that of the second upperpad electrode 503 formed on an uppermost surface of the second padelectrode 500. For example, when the second pad electrode 500 ispattern-formed, it may be desirable to prevent a pattern of the firstcover pad electrode 403 from being damaged. As such, the second padelectrode 500 may be formed through a process in which an electrodematerial for the second center pad electrode 502 and an electrodematerial for the second upper pad electrode 503 may be sequentiallydeposited, the second upper pad electrode 503 may be pattern-formed byetching the electrode material for the second center pad electrode 502,and the second center pad electrode 502 may be subsequentlypattern-formed by etching the electrode material for the second upperpad electrode 503. That is, the first cover pad electrode 403 may becovered by the electrode material for the second center pad electrode502 when etching the electrode material for the second upper padelectrode 503. Thus, an etchant for etching the electrode material forthe second upper pad electrode 503 may not be brought into contact withthe first cover pad electrode 403, thereby preventing a pattern of thefirst upper pad electrode 403 from being damaged.

Subsequently, as shown in FIG. 5F, a bank 220 may be formed on bothsides of the second anode electrode 200 to expose a top of the secondanode electrode 200. Also, the bank 220 may be formed on both sides ofthe second auxiliary electrode 210 to expose a top of the secondauxiliary electrode 210. Also, a first partition wall 231 and a secondpartition wall 232 may be sequentially formed on the exposed top of thesecond auxiliary electrode 210. The partition wall 230 may be formed tobe separated from the bank 220 by a certain (e.g., a predetermined)distance. Thus, a separation space may be provided between the partitionwall 230 and the bank 220. Such a process is similar to theabove-described process of FIG. 4I.

Subsequently, as shown in FIG. 5G, an organic emission layer 240 may beformed on the second anode electrode 200. The organic emission layer 240may be deposited on top of the bank 220 and the partition wall 230, butis not deposited in the separation space between the partition wall 230and the bank 220. Such a process is similar to the above-describedprocess of FIG. 4J.

Subsequently, as shown in FIG. 5H, a cathode electrode 250 may be formedon the organic emission layer 240. The cathode electrode 250 may beformed to be connected to the second auxiliary electrode 210 through theseparation space between the partition wall 230 and the bank 220. Such aprocess is similar to the above-described process of FIG. 4K.

According to embodiments of the present disclosure, the first padelectrode may be formed to cover the top of the signal pad, therebypreventing the signal pad from being corroded. Accordingly, the signalpad may be formed in a two-layer structure which may include the lowersignal pad and the upper signal pad vulnerable to corrosion. Forexample, because the first pad electrode and the first auxiliaryelectrode may be simultaneously formed of the same material, the numberof mask processes may not increase. Moreover, according to embodimentsof the present disclosure, the contact hole for externally exposing thesource electrode and the contact hole for externally exposing the signalpad may be simultaneously formed. Thus, the number of mask processes maynot increase.

Moreover, according to embodiments of the present disclosure, the twoauxiliary electrodes (for example, the first and second auxiliaryelectrodes) may be formed for lowering the resistance of the cathodeelectrode. Thus, the desired resistance characteristic of the auxiliaryelectrode may be more easily adjusted. For example, the first auxiliaryelectrode connected to the second auxiliary electrode through thecontact hole may be further formed under the second auxiliary electrode,and the resistance of the cathode electrode may be effectively loweredeven without any reduction in a pixel area.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present disclosurewithout departing from the spirit or scope of the invention. Thus, it isintended that embodiments of the present disclosure cover themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

What is claimed is:
 1. An organic light-emitting display apparatus,comprising: a substrate comprising an active area and a pad area; ananode electrode in the active area of the substrate; an organic emissionlayer on the anode electrode; a cathode electrode on the organicemission layer; an auxiliary electrode in the active area of thesubstrate and directly connected to the cathode electrode; a signal padin the pad area of the substrate; and a first pad electrode connected tothe signal pad, the first pad electrode covering a top of the signalpad, the first pad electrode being configured to prevent the top of thesignal pad from being corroded, wherein the auxiliary electrodecomprises a first auxiliary electrode and a second auxiliary electrodeconnected to the first auxiliary electrode through a contact hole, andwherein the first pad electrode comprises a same material as the firstauxiliary electrode.
 2. The organic light-emitting display apparatus ofclaim 1, wherein: the first pad electrode comprises: a first lower padelectrode; a first upper pad electrode; and a first cover pad electrode,the first cover pad electrode covers a top and a side surface of thefirst upper pad electrode, and the first cover pad electrode has a loweroxidation rate than the top of the signal pad.
 3. The organiclight-emitting display apparatus of claim 2, wherein: the firstauxiliary electrode comprises: a first lower auxiliary electrode; afirst upper auxiliary electrode; and a first cover auxiliary electrode;the first lower pad electrode comprises a same material as the firstlower auxiliary electrode; the first upper pad electrode comprises asame material as the first upper auxiliary electrode; and the firstcover pad electrode comprises a same material as the first coverauxiliary electrode.
 4. The organic light-emitting display apparatus ofclaim 1, wherein: the anode electrode comprises a first anode electrodeand a second anode electrode connected to the first anode electrodethrough a contact hole; and a width of the first auxiliary electrode isgreater than a width of the first anode electrode.
 5. The organiclight-emitting display apparatus of claim 4, wherein the first auxiliaryelectrode overlaps the second anode electrode.
 6. The organiclight-emitting display apparatus of claim 1, further comprising a secondpad electrode on the first pad electrode.
 7. The organic light-emittingdisplay apparatus of claim 6, wherein the second pad electrode comprisesa same material as the second auxiliary electrode.
 8. The organiclight-emitting display apparatus of claim 1, wherein: the signal padcomprises: a lower signal pad; and an upper signal pad; an oxidationrate of the lower signal pad is lower than an oxidation rate of theupper signal pad; and a resistance of the upper signal pad is lower thana resistance of the lower signal pad.
 9. The organic light-emittingdisplay apparatus of claim 1, further comprising: a bank on both sidesof the second auxiliary electrode; and a partition wall on the secondauxiliary electrode, the partition wall being separated from the bank,wherein the cathode electrode is connected to the second auxiliaryelectrode through a separation space between the bank and the partitionwall.